Junction barrier schottky with low forward drop and improved reverse block voltage

Abstract

This invention discloses a junction barrier Schottky device supported on a substrate that has a first conductivity type. The Schottky device includes a first diffusion region of a first conductivity type for functioning as a forward barrier height reduction region. The Schottky device further includes a second diffusion region of a second conductivity type disposed immediately adjacent to the first diffusion region for functioning as a backward blocking enhancement region to reduce the backward leakage current.

1. A junction barrier Schottky device comprising:
 a first semiconductor layer of a first conductivity type and a second semiconductor layer disposed above and having a lower impurity concentration of said first conductivity type than said first semiconductor layer; 
 a first diffusion region of said first conductivity type having a higher impurities concentration than said impurity concentration of the second semiconductor layer, for functioning as a forward barrier height reduction region; 
 a second diffusion region of a second conductivity type disposed adjacent to said first diffusion region for functioning as a backward blocking enhancement region and said first and second diffusion regions disposed above said second semiconductor layer; and 
 a terminal semiconductor region of said first conductivity disposed above said second semiconductor layer, and having a lower impurity concentration than said second semiconductor layer wherein said terminal semiconductor region disposed near a terminal edge in said junction barrier Schottky device. 
 
   
   
     2. The junction barrier Schottky device of  claim 1  further comprising:
 a plurality of said first diffusion and second diffusion regions disposed alternately adjacent to each other. 
 
   
   
     3. The junction barrier Schottky device of  claim 1  further comprising:
 a plurality of said first diffusion and second diffusion regions disposed alternately adjacent to each other having a prescribed width as a prescribed interval between every two of said first and second diffusion regions. 
 
   
   
     4. The junction barrier Schottky device of  claim 1  further comprising:
 a plurality of said first diffusion and second diffusion regions formed by a simultaneous diffusion of ions of said first and second conductivity into said second semiconductor layer. 
 
   
   
     5. The junction barrier Schottky device of  claim 1  further comprising:
 a plurality of said first diffusion and second diffusion regions formed by a simultaneous diffusion of ions of said first and second conductivity into said second semiconductor layer wherein said ions of said first and second conductivity types each having different vertical and lateral diffusion coefficients. 
 
   
   
     6. The junction barrier Schottky device of  claim 1  further comprising:
 a plurality of said first diffusion and second diffusion regions formed by a simultaneous diffusion of ions of said first conductivity type of N type ions and said second conductivity type of P type ions into said second semiconductor layer wherein each of said N-type and P-type ions having different vertical arid lateral diffusion coefficients. 
 
   
   
     7. The junction barrier Schottky device of  claim 1  further comprising:
 a plurality of said first diffusion and second diffusion regions formed by a simultaneous diffusion of ions of said first conductivity type of N-type ions and said second conductivity type of P-type ions into said second semiconductor layer wherein said N-type ions having a higher lateral diffusion coefficient than a vertical diffusion coefficient and said P-type ions having higher vertical diffusion coefficient than a lateral diffusion coefficient. 
 
   
   
     8. The junction barrier Schottky device of  claim 1  further comprising:
 a plurality of said first diffusion and second diffusion regions disposed formed by a simultaneous diffusion of ions of said first and second conductivity into said second semiconductor layer with each of said first and second diffusion regions having a prescribed width disposed as neighboring regions adjacent to each other. 
 
   
   
     9. The junction barrier Schottky device of  claim 1  further comprising:
 an anode and a cathode electrodes for applying a voltage over said substrate. 
 
   
   
     10. The junction barrier Schottky device of  claim 9  wherein:
 one of said electrodes further comprising a conductive layer covering a top surface of said substrate for contacting said first and second diffusion regions. 
 
   
   
     11. The junction barrier Schottky device of  claim 10  wherein:
 said conductive layer further comprising a silicide layer covering a top surface of said substrate for contacting said first and second diffusion regions. 
 
   
   
     12. The junction barrier Schottky device of  claim 10  wherein:
 said conductive layer further comprising a metal layer covering a top surface of said substrate for contacting said first and second diffusion regions. 
 
   
   
     13. The junction barrier Schottky device of  claim 2  wherein:
 at least one of second diffusion regions disposed in a termination area serving as a guard ring for breakdown voltage sustaining. 
 
   
   
     14. The junction barrier Schottky device of  claim 10  wherein:
 another electrode is formed on a bottom surface opposite said top surface contacting said first semiconductor layer.